JEWEL SAMAD/AFP/Getty Images(UPPER MARLBORO, Md.) -- Using his executive authority to combat climate change, President Obama on Tuesday announced plans to further tighten fuel efficiency standards for medium- and heavy-duty trucks.

“The goal we're setting is ambitious. But these are areas where ambition has worked out really well for us so far. Don't make small plans, make big plans,” Obama said, as he stood before two massive trucks at the Safeway Distribution Center in Upper Marlboro, Md.

The president directed the Environmental Protection Agency and Transportation Department to develop and issue new fuel efficiency and greenhouse gas standards by March 31, 2016, building on the stricter standards set in 2011. The administration has not yet indicated the new reduction level it hopes to achieve.

Although heavy-duty trucks account for just 4 percent of vehicles on the nation’s roadways, they’re responsible for roughly 25 percent of carbon pollution and on-road fuel consumption, according to the White House.

Tuesday’s announcement is the latest unilateral effort in the president’s “year of action,” as he tries to circumvent gridlock in Congress to enact his agenda.

“Every time somebody says, you can't grow the economy while bringing down pollution, it's turned out they've been wrong,” the president said to applause. “Anybody who says we can't compete when it comes to clean energy technologies like solar and wind, they've had to eat those words. You can't bet against American workers or American industry.”

Safeway was picked as the location for Tuesday’s event because the company has been a leader in improving trucking efficiency, according to a White House official.

“I have a little soft-spot for Safeway in my heart because some of you know I went to high school in Hawaii and I was living with my grandparents. Our main grocery store was Safeway, it was right down the way,” Obama said at the top of his remarks. “And so my grandmother would send me off to go shopping at Safeway. And everybody there always treated me very well.”